Sheaves and the like are known in the art and may be used to alter the direction of force and/or provide drive to a line, amongst other purposes.
When sheaves are used in a line driving application, there is a constant challenge to achieve desired friction between the drive sheave (often referred to as the "drum") and the line, while not causing undue wear in the sheave or line. Slippage of the line within the sheave results in the consumption of additional energy, wear of components and an increase in fire potential due to sparking, etc.
Known sheave arrangements for slack pulling carriages include those that have a generally U-shaped circumferential groove that approximates the diameter of a line to be used therein and a plurality of weld beads at the bottom or sides of the groove. The weld beads improve friction (or traction) between the drum and the line (like studs on a studded snow tire), but induce wear in the line and sheave at a disadvantageously rapid rate. The undesirable rate of line wear is not only economically disadvantageous in that the line and/or sheave must be replaced, but also raises significant safety concerns.
A need thus exists for a sheave arrangement that provides desired friction without unreasonable wear. This need exists in many driving sheave applications, including but not limited to, slack pulling carriages and related equipment.